[PATCH] preliminary sata_promise ATAPI support

[Mikael Pettersson <mikpe@it.uu.se>]

This patch against 2.6.20-rc2 adds partial ATAPI support to
the sata_promise driver. This patch is preliminary and for
review only.

Current Status:
- Tested with PATA optical devices on 20378 and 20575 chips.
- Mounting and reading CD/DVD discs in DMA mode works fine.
- Using cdrecord to write CD-R discs works if DMA mode is
  disabled (s/0/1/ in pdc_check_atapi_dma()). With DMA enabled,
  cdrecord first complains that capability checking commands
  fail, and then fails to write due to error interrupts.

The most delicate change is pdc_issue_atapi_pkt_cmd(), which is
ported from Promise's pdc-ultra/pdc-ulsata2 drivers. There's no
documentation to explain why this code is needed, but it looks
to me as if these steps should have been done in a taskfile, but
for some reason they need to do them manually.

As to why CD-writing fails with DMA enabled, I suspect that I
either need to blacklist specific packet commands from using
DMA, or I have some bug in pdc_qc_prep() or pdc_qc_issue_prot()
for the ATA_PROT_ATAPI_DMA case.

To use this with PATA optical devices you also need the forever
pending sata_promise PATA patches. I didn't want ATAPI support
to be delayed by those, so I based ATAPI on the vanilla kernel
and rebased PATA on top of ATAPI; you can get my sata_promise
patch kit from <http://www.csd.uu.se/~mikpe/linux/patches/2.6/>.

I should be able to do some testing with a SATA ATAPI CD/DVD writer
later next week.

/Mikael

diff -rupN linux-2.6.20-rc2/drivers/ata/sata_promise.c linux-2.6.20-rc2.sata_promise-atapi-wip-1/drivers/ata/sata_promise.c
--- linux-2.6.20-rc2/drivers/ata/sata_promise.c	2006-12-24 13:21:26.000000000 +0100
+++ linux-2.6.20-rc2.sata_promise-atapi-wip-1/drivers/ata/sata_promise.c	2006-12-30 16:58:46.000000000 +0100
@@ -105,6 +105,7 @@ static void pdc_pata_phy_reset(struct at
 static void pdc_qc_prep(struct ata_queued_cmd *qc);
 static void pdc_tf_load_mmio(struct ata_port *ap, const struct ata_taskfile *tf);
 static void pdc_exec_command_mmio(struct ata_port *ap, const struct ata_taskfile *tf);
+static int pdc_check_atapi_dma(struct ata_queued_cmd *qc);
 static void pdc_irq_clear(struct ata_port *ap);
 static unsigned int pdc_qc_issue_prot(struct ata_queued_cmd *qc);
 static void pdc_host_stop(struct ata_host *host);
@@ -139,6 +140,7 @@ static const struct ata_port_operations 
 	.check_status		= ata_check_status,
 	.exec_command		= pdc_exec_command_mmio,
 	.dev_select		= ata_std_dev_select,
+	.check_atapi_dma	= pdc_check_atapi_dma,
 
 	.qc_prep		= pdc_qc_prep,
 	.qc_issue		= pdc_qc_issue_prot,
@@ -183,7 +185,7 @@ static const struct ata_port_info pdc_po
 	/* board_2037x */
 	{
 		.sht		= &pdc_ata_sht,
-		.flags		= PDC_COMMON_FLAGS | ATA_FLAG_SATA,
+		.flags		= (PDC_COMMON_FLAGS & ~ATA_FLAG_NO_ATAPI) | ATA_FLAG_SATA,
 		.pio_mask	= 0x1f, /* pio0-4 */
 		.mwdma_mask	= 0x07, /* mwdma0-2 */
 		.udma_mask	= 0x7f, /* udma0-6 ; FIXME */
@@ -213,7 +215,7 @@ static const struct ata_port_info pdc_po
 	/* board_2057x */
 	{
 		.sht		= &pdc_ata_sht,
-		.flags		= PDC_COMMON_FLAGS | ATA_FLAG_SATA,
+		.flags		= (PDC_COMMON_FLAGS & ~ATA_FLAG_NO_ATAPI) | ATA_FLAG_SATA,
 		.pio_mask	= 0x1f, /* pio0-4 */
 		.mwdma_mask	= 0x07, /* mwdma0-2 */
 		.udma_mask	= 0x7f, /* udma0-6 ; FIXME */
@@ -415,6 +417,30 @@ static void pdc_qc_prep(struct ata_queue
 		pdc_pkt_footer(&qc->tf, pp->pkt, i);
 		break;
 
+	case ATA_PROT_ATAPI:
+	case ATA_PROT_ATAPI_NODATA:
+		ata_qc_prep(qc);
+		break;
+
+	case ATA_PROT_ATAPI_DMA:
+		ata_qc_prep(qc);
+		/* let pdc_pkt_header() set up the header proper (12 bytes),
+		   it will set up another 4 bytes too which we'll overwrite */
+		qc->tf.protocol = ATA_PROT_DMA;
+		pdc_pkt_header(&qc->tf, qc->ap->prd_dma, qc->dev->devno, pp->pkt);
+		qc->tf.protocol = ATA_PROT_ATAPI_DMA;
+		if (qc->dev->cdb_len & ~0x1E) { /* 2/4/6/8/10/12/14/16 are Ok */
+			printk(KERN_ERR "%s: bad cdb_len %u\n", __FUNCTION__, qc->dev->cdb_len);
+			BUG();
+		}
+		pp->pkt[12] = (((qc->dev->cdb_len >> 1) & 7) << 5) | 0x00 | 0x08;
+		memcpy(pp->pkt+13, qc->cdb, qc->dev->cdb_len);
+#if 0
+		/* pdc-ultra/cam/cam_ata.c will pad SG length to a multiple
+		   of 4 here, but libata has already done that for us */
+#endif
+		break;
+
 	default:
 		break;
 	}
@@ -528,6 +554,7 @@ static inline unsigned int pdc_host_intr
 	switch (qc->tf.protocol) {
 	case ATA_PROT_DMA:
 	case ATA_PROT_NODATA:
+	case ATA_PROT_ATAPI_DMA:
 		qc->err_mask |= ac_err_mask(ata_wait_idle(ap));
 		ata_qc_complete(qc);
 		handled = 1;
@@ -615,6 +642,7 @@ static inline void pdc_packet_start(stru
 
 	VPRINTK("ENTER, ap %p\n", ap);
 
+	/* XXX: for SATAII ATAPI PIO write SEQ_FPDMA (1<<6) not PacketCount */
 	writel(0x00000001, ap->host->mmio_base + (seq * 4));
 	readl(ap->host->mmio_base + (seq * 4));	/* flush */
 
@@ -624,16 +652,115 @@ static inline void pdc_packet_start(stru
 	readl((void __iomem *) ap->ioaddr.cmd_addr + PDC_PKT_SUBMIT); /* flush */
 }
 
+static unsigned int pdc_wait_on_busy(struct ata_port *ap)
+{ 
+	/* ata_busy_wait() loops reading status while pdc-ultra's WaitOnBusy()
+	 * loops reading altstatus. Both approaches seem to work here.
+	 */
+	unsigned int status = ata_busy_wait(ap, ATA_BUSY, 1000);
+	if (status != 0xff && (status & ATA_BUSY))
+		printk("%s: port %u: timed out, status %#x\n", __FUNCTION__, ap->port_no, status);
+	return status;
+}
+
+static unsigned int pdc_wait_for_drq(struct ata_port *ap)
+{ 
+	void __iomem *port_mmio = (void __iomem *) ap->ioaddr.cmd_addr;
+	unsigned int i;
+	unsigned int status;
+
+	/* Following pdc-ultra's WaitForDrq() we loop here until BSY
+	 * is clear and DRQ is set in altstatus. We could possibly call
+	 * ata_busy_wait() and loop until DRQ is set, but since we don't
+	 * know how much time a call to ata_busy_wait() took, we don't
+	 * know when to time out the outer loop.
+	 */
+	for(i = 0; i < 1000; ++i) {
+		status = readb(port_mmio + 0x38); /* altstatus */
+		if (status == 0xFF)
+			break;
+		if (status & ATA_BUSY)
+			;
+		else if (status & (ATA_DRQ | ATA_ERR))
+			break;
+		mdelay(1);
+	}
+	if (i >= 1000)
+		printk("%s: port %u: timed out\n", __FUNCTION__, ap->port_no);
+	return status;
+}
+
+static void pdc_issue_atapi_pkt_cmd(struct ata_queued_cmd *qc)
+{
+	struct ata_port *ap = qc->ap;
+	void __iomem *port_mmio = (void __iomem *) ap->ioaddr.cmd_addr;
+	void __iomem *host_mmio = ap->host->mmio_base;
+	unsigned int nbytes;
+	unsigned int tmp;
+
+	/* disable INTA here, it will be re-enable when CAM use SEQ 0 for packets */
+	writeb(0x00, port_mmio + PDC_CTLSTAT); /* that the drive INT pass to SEQ 0*/
+	writeb(0x20, host_mmio + 0); /* but mask SEQ 0 INT */
+
+	/* select drive */
+	if (sata_scr_valid(ap)) {
+		tmp = 0xE0;
+	} else {
+		tmp = ATA_DEVICE_OBS;
+		if (qc->dev->devno != 0)
+			tmp |= ATA_DEV1;
+	}
+	writeb(tmp, port_mmio + 0x18); /* device/head */
+	pdc_wait_on_busy(ap);
+
+	writeb(0x00, port_mmio + 0x08); /* sector count */
+	writeb(0x00, port_mmio + 0x0c); /* sector number */
+
+	/* set feature register */
+	if (qc->tf.protocol != ATA_PROT_ATAPI_DMA) {
+		tmp = 0x00; /* data xfer by PIO ! */
+		/* set real transfer byte count to byte counter register (cylinder low/high) */	
+		nbytes = qc->nbytes;
+		if (!nbytes)
+			nbytes = qc->nsect << 9;
+		if (nbytes > 0xffff)
+			nbytes = 0xffff;
+	} else {
+		tmp = 0x01; /* set DMA bit */
+		/* byte counter register (cylinder low/high) , set to 0 */
+		nbytes = 0;
+	}
+	writeb(tmp, port_mmio + 0x04); /* feature */
+	writeb(nbytes & 0xFF, port_mmio + 0x10); /* cylinder low */
+	writeb((nbytes >> 8) & 0xFF, port_mmio + 0x14); /* cylinder high */
+
+	/* send ATAPI packet command 0xA0 */
+	writeb(ATA_CMD_PACKET, port_mmio + 0x1c); /* command/status */
+
+#if 0 /* XXX: don't know if this is relevant or how to realize the test */
+	/* Do we have to wait INT ? */	
+	if (the device interrupts with assertion of DRQ after receiving ATAPI packet command)
+		WaitForINT(ap);
+#endif
+
+	pdc_wait_for_drq(ap);
+
+	/* now device wait CDB only */
+}
+
 static unsigned int pdc_qc_issue_prot(struct ata_queued_cmd *qc)
 {
 	switch (qc->tf.protocol) {
+	case ATA_PROT_ATAPI_DMA:
+		pdc_issue_atapi_pkt_cmd(qc);
+		/*FALLTHROUGH*/
 	case ATA_PROT_DMA:
 	case ATA_PROT_NODATA:
 		pdc_packet_start(qc);
 		return 0;
 
-	case ATA_PROT_ATAPI_DMA:
-		BUG();
+	case ATA_PROT_ATAPI:
+	case ATA_PROT_ATAPI_NODATA:
 		break;
 
 	default:
@@ -658,6 +785,10 @@ static void pdc_exec_command_mmio(struct
 	ata_exec_command(ap, tf);
 }
 
+static int pdc_check_atapi_dma(struct ata_queued_cmd *qc)
+{
+	return 0;	/* ATAPI DMA is supported */
+}
 
 static void pdc_ata_setup_port(struct ata_ioports *port, unsigned long base)
 {
-
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